1. Technical Field
This invention relates in general to coin grading, and more particularly, to a method and system for accurately and objectively evaluating the numismatic quality of a coin and/or for identifying the coin.
2. Definitions
The following terms and phrases are used herein in accordance with the following meanings:
1. Coins--collectible pieces, including metallic money, tokens, medals, medallions, rounds, etc.
2. Obverse/Reverse--obverse is the side of the coin bearing the more important legends or types; its opposite side is the reverse.
3. Circulated/Uncirculated--circulation is the act of transferring a coin from place to place or person to person in the normal course of business; uncirculated is interchangable with "mint state" and refers to a coin which has never been circulated.
4. Detracting Marks--marks on a coin which have occurred after minting, for example: (a) bag marks, i.e., any nick, small cut or similar mark on the surface of a coin resulting from coins contacting each other within mint bags, while in storage at the Treasury Department or bank vaults, or during transportation prior to circulation; (b) scratch/gouge marks, i.e., grooves or other markings on a coin surface resulting from careless handling; and (c) friction wear, e.g., cabinet wear, pocket wear, etc., if visible to the naked eye or under small magnification, such as 2.times. or 4.times. magnification.
5. Macroscopic/Microscopic--macroscopic markings are visible to the naked eye; microscopic markings require a microscope to be viewed.
6. Mint Luster--the sheen or "bloom" on the surface of a coin created by radial die marks, which are produced by minute imperfections or rough spots on the surface of the dies used to form the coin and by the centrifugal flow of metal when struck by those dies.
7. Tampering--treating or processing a coin to give it the appearance of being of a higher grade than it actually is. Types of processing include: polishing or abrasion, which remove metal from a coin surface; etching, and acid treatment; "whizzing"; etc. Whizzing usually refers to abrating the surface of a coin with a wire brush to produce a series of minute, tiny parallel scratches which to the unaided eye or under low magnification often appear to be like mint luster.
8. Strength of Strike--refers to the sharpness of design details within a coin. A sharp strike or strong strike is one with all the details struck very clearly; a weak strike has the details lightly impressed at the time of coining.
3. Description of Prior Art
Although people have been collecting coins since the days of antiquity, it is only in recent times that coin values have greatly increased. One of the main determining factors of a coin's value is its grade, i.e., the condition or state of wear of the coin. A very small difference in grade can mean a large difference in price, thus making the exact grade of a coin important, especially today.
At present, two coin grading systems are prevalent. One expresses a coin's state in words or letters, the other uses a combination of letters and numbers. In the first system, the most important terms in ascending order are: good (G); very good (VG); fine (F); very fine (VF); extremely fine (EF), (XF); about uncirculated (AU); uncirculated or mint state (MS). The second system is based on an alphanumerical scale in which 1 represents the worst possible condition of preservation of a coin and 70 represents the best possible condition. In this system, a coin in uncirculated condition or mint state is referred to or categorized as an MS60 through MS70 coin.
The monetary value of a coin does not increase linerally as the coin advances within the different levels or categories of coin grades. As much as 95% of the potential monetary value of a coin may rest in being classified as an "uncirculated" (MS60 through MS70), or at least as an "about uncirculated" (AU50 through AU59) coin. In fact, the difference between one or two grade levels within these classes and particularly for mint state coins, may affect the value of a coin anywhere from hundreds to thousands of dollars.
Traditionally, a main difficulty inherent in classifying a coin within one of the above categories has been in defining what exactly is meant by the term designating a particular category. More obvious, however, has been the difficulty inherent in matching a particular test coin with one of the predefined grade categories since all grading to date has at least in part involved a subjective evaluation(s) by an appraiser or numismatist.
Known methods for defining what is meant by a particular grade category comprise either the use of textual descriptions, lined drawings, photographs or facsimile coins. With each of these methods, the category to which a coin is assigned ultimately depends to a large extent upon the numismatist conducting the evaluation. For example, textual descriptions of categories are susceptible to different interpretations by different individuals. Lined drawings often do not accurately represent the characteristics of actual coins and are normally utilized only to represent one particular type of defect or imperfection. Photographs and facsimile coins are often representative of a combination of types of defects which should be considered in evaluating coins, such as a photograph or facsimile coin illustrating visible wear and numerous bag marks. Clearly, such a guide provides a difficult standard and one which is open to various interpretations, especially, e.g., should no wear be visible but bag marks present on the test coin under evaluation.
Further, even if the grading system categories are understood by an individual, most, if not all, prior art methods of evaluating coins require the numismatist to subjectively match a particular test coin with a grade category. The principal factors to an accurate prior art appraisal of a coin are the appraiser's skill and experience, the lack of which can result in a particular coin being categorized significantly different than its true grade. However, even with an experienced appraiser, a particular coin may be categorized differently based upon environmental factors such as, the time of day, the presence or absence of magnification, and the type and amount of lighting applied to the surface of the coin.
The problems inherent in subjective grading methods have been highlighted and intensifed by the recent expansion of the number of grade system categories being used, e.g., from three or four previously used uncirculated categories to the eleven (MS60 through MS70) now used by some appraisers. A commonly heard complaint in the grading industry is that it is simply impossible to consistently and accurately categorize a coin with such a large number of grade levels. In response to this, at least one grading firm is requiring that each submission be evaluated by five recognized numismatists and that four of the five independently agree as to the grade category of the coin. Although such a program does result in a more accurate grading of coins, it is obviously a very costly and time consuming operation.
Another approach to addressing the subjectiveness problems of today's coin grading techniques is disclosed by Mason in U.S. Pat. No. 4,191,472. In Mason, apparatus is provided to assist an individual in evaluating some of the more important factors which influence the grade of a coin. This apparatus comprises sets of facsimile coins, for a given class or issue, representative of particular types of coin defects or imperfections. The facsimile coins within each set are arranged according to increasing or decreasing extents to which the coin defect is exhibited. Each of the facsimile coins has assigned to it a number representative of the relative value thereof based upon the extent to which the facsimile exhibits the particular coin defect. The numeric values of the facsimile coins which exhibit the defects to the same extent (roughly) as a test coin are noted and summed to arrive at a total numeric value for the coin. The monetary value or grade of the test coin is then determined with reference to tables which correlate the total numeric value of the test coin to a monetary value.
Although it is claimed in Mason that the described apparatus allows for the "objective" evaluation of coins, a subjective interpretation of the various facsimile coin definitions and matching of a test coin to a parcticular definition is still required. Mason simply assists the appraiser by directing his attention to some of the individual factors which comprise the various grade levels. Further, Mason only provides for consideration of selected factors such as bag marks, and coin luster, and does not address equally important considerations such as the location of the bag marks on the surface of the coin.
An issue closely related to coin grading involves the identification of lost or stolen coins. The importance of "fingerprinting" collectable coins for future identification is also of greater importance today as the value of such coins has increased. Presently, a coin is traced and identified via stored photographs of the coin, which are typically taken at the time the coin is graded. This procedure is sufficiently accurate, yet it is very time consuming to initially record the coins and then to subsequently search through a large number of coin photographs to identify a particular coin, much too time consuming to undertake with each coin being graded, at least not without first having a suspicion that a particular coin has been previously reported as lost or stolen.
Therefore, there presently exists a genuine need for an accurate and fully objective system for categorizing a coin at an appropriate grade level and for "fingerprinting" coins for recordation and subsequent comparison with other coins.